ECONOMIC VALUE OF EXAMINATIONS - 
Percentage Hired Efficiency Percentage Hired 
hy Old Examinations of Employees by New Examinations 
0 High [ we 
Above Average mT | 349%, 
Z. Below Average [1 7% 
& Low 07, 
0 wm 0 0 SR DRE SE NY 
Percentage Percentage. 
Figure 30: Comparison of old and new types of civil service examinations 
for the selection of postal employees (124). 
interviewers gave a zero correlation. The criterion and the 
intelligence test gave a correlation of .51. 
While making an investigation in the interest of the postal 
service, O'Rourke (124) compared the validity of a new 
type of examination with the type long in use, in the selec- 
tion of mail sorters. His comparisons are shown in Figure 
30. His complete report is recommended to the reader for 
its excellent analysis of improvements which scientific meth- 
ods of selection make possible. 
In this connection it may be suggested that no recom- 
mendation be made looking toward the exclusive use of tests. 
The interview is valuable for the elimination of individuals 
who are unsuited for the vocation because of abilities not 
ordinarily measurable by tests. Interviewers, however, 
should be provided with rating scales as aids in judging 
applicants. These scales should be as objective as possible 
and the predictive value of the material they cover should 
have been evaluated the same as test scores. The interview 
and the tests should supplement each other. 
The investigator will find it advisable to present in graphic 
form the results of his comparative evaluation (157, 20). 
217